High frequency sound energy produced by dental aspirators is a constant source of irritation, not only to the patient, but also for dental practitioners exposed thereto for long periods of time and may cause hearing problems, stress and fatigue.
A dental aspirator comprises a suction tube, the free end of which is inserted into a patient's mouth to remove water, saliva and solid material from the patient's mouth. High frequency sound energy or noise is generated by the air or air/liquid mixture being drawn into the intake orifice and forced down the suction tube of the aspirator.
The problem also arises in other areas of dental/medical practise, such as surgical vacuum systems used for the removal of air/liquid/blood during surgery, as well as laser fume extraction systems.
Apart from the noise which is generated, a further problem which arises is that of "suck back", which occurs when the suction orifice is blocked by tissue in or around the operation site. Since this can result in bacterial and viral cross-infection, it has become a cause for concern in medicine and dentistry.
In addition to the above examples given in respect of the medical field, noise reduction is also important in other areas, such as in industrial applications, e.g. vacuum intake or exhaust systems, as well as high pressure steam exhaust systems and high frequency sound energy associated with jet engines.